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    <script>
        // 5. 编写函数has(arr , 60) 判断数组中是否存在60这个元素，返回布尔类型
        var arr = [1, 2, 3, 60]
        var arr2 = [1, 2, 3]
        
        function has(a,num) {
            for(var i = 0 ; i < a.length;i++){
                if(a[i] === num){
                    return true
                } 
            }
            return false
        }
        
        console.log(has(arr, 60)) // true
        console.log(has(arr2, 60)) // false
    </script>
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